Pleural diseases are frequent medical problems often requiring expensive inpatient treatments, often of an invasive or surgical nature. Non-limiting examples of pleural diseases include pleural effusions and pneumothorax. Pleural effusions are build-ups of fluid around the lung, and pneumothorax (PTX) is the collapse of the lung due to air entering the pleural space.
Pleural effusions can be caused by a variety of common medical conditions such as cancer, tuberculosis, congestive heart failure, pneumonia, pulmonary emboli, cirrhosis with ascites, pancreatitis, or collagen vascular disease. If the amount of fluid is significant, the lung is compressed and the patient experiences shortness of breath and cough. These effusions are often difficult to treat and result in recurrent shortness of breath as well as frequent hospital visits for multiple treatments. There are many different elements that should be taken into consideration for the treatment and management of pleural effusions, particularly malignant pleural effusions. See American Thoracic Society, Management of Malignant Pleural Effusions, 162 AM. J. OF RESPIRATORY AND CRITICAL CARE 1987-2001 (2000, incorporated herein by reference).
In view of the burden and suffering attributable to pleural effusions and of the nature of the patient population suffering from it, a preferred treatment approach should offer immediate and long term relief of symptoms, avoid hospitalization, be applicable to the majority of patients, have minimal side effects and avoid repeated uncomfortable procedures.
The usual approach to patients with symptomatic malignant pleural effusion (MPE) is to perform repeated pleural taps (thoracentesis), or to attempt pleurodesis with a sclerosing agent such as talc or a tetracycline by placing an intercostal catheter or via surgical thoracoscopy and attempt pleurodesis with a sclerosing agent such as talc or a tetracycline. The first approach is resource intensive (requiring multiple visits to physician or ultrasound department), painful and only partially and temporarily effective in relieving symptoms. The second requires hospitalization, and may require a general anesthetic. It can also only be performed in a portion of patient who undergo chest tube placement, can be significantly painful and has been associated with severe pulmonary complications.
A newer outpatient procedure, the Pleurx, has been developed by Denver Biomed, Inc. (now part of Cardinal Health) using a long-term tunneled catheter inserted into the pleural space. Unfortunately, the majority of patients need ongoing drainage with the catheter for the rest of their life, although some patients achieve a pleurodesis after an average of approximately 8-12 weeks of drainage. This prolonged drainage has potential impacts on quality of life, complication rates (due to infections), cost of supplies and nutritional status.
Primary spontaneous pneumothorax (PSP) is a pneumothorax in patients without a pre-existing lung disease. Secondary spontaneous pneumothorax (SSP) is a pneumothorax occurring in patients with a variety of lung diseases such as chronic obstructive pulmonary disease (COPD), emphysema, or pulmonary fibrosis. The majority of pneumothorax cases can be treated with simple chest tube drainage. Although patients who experience a pneumothorax are at high risk of a recurrent event in the future, patients are not generally offered treatment aimed to reduce that risk until they experience two or more episodes of lung collapse given the invasive nature of currently available preventative treatments.
Patients with severe heart failure can develop recurrent pleural effusions complicating their care and causing increased breathing difficulties. Given the lack of effective and safe local treatments for these effusions, only optimization of the cardiac function can lead to the resolution of the problem. Unfortunately, recurrence of the fluid build up is frequent.
A safe, minimally invasive and effective method to achieve long term control of pneumothorax or non-malignant pleural effusions would be of great benefit to these patients.